• Korean Journal of Veterinary Pathology
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• v.5 no.2
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• pp.49-56
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• 2001

Ocular lesions induced in 40 specific-pathogen-free Marek's disease (MD) resistant chicks by inoculation at 1 day of age with very virulent strain of Marek's disease virus (WV) were pathologically examined. Grossly,24/40 (60%) chicks had white gel-like materials in the vitreous body, whereas thickening and discoloration of iris (gray eye) were not observed. Microscopically, characteristic ocular MD lesions were observed in choroid (27/40), ciliary (30/40) and iris (23/40) in which small focal inflammatory to diffuse neoplastic Iymphoid cells were infiltrated. Five out of 40 MDV-inoculated birds revealed necrotizing Iymphomas in choroid. These lesions consisted of necrotic and degenerating Iymphoblasts accompanied by intranuclear inclusion body. There was retinal atrophy and necrosis with inclusion body detected in necrotic ganglion, inner or outer nuclear and infiltrated Iymphoblast cells. Conjunctiva showed lymphoid cell infiltration in 29/40 chicks inoculated with MDV, Vitreous body exhibited mild to severe exudation of eosinophilic proteinaceous material in 24/40 chicks. These lesions were associated with Iymphoid cell infutration, edema and fibrosis of choroid. Pecten (7/40) and optic nerve (13/40) were infiltrated usually mildly with Iymphoid cells. From these results, very virulent strain, Md/5 of MDV caused high incidence of ocular lesions in MD resistant chicks. In addition, Md/5 induced exudation of proteinaceous material into the vitreous body and fibrosis of choroid. Necrotizing ocular Iymphoma lesions in choroid is the first report in the MD literature.

• Korean Journal of Veterinary Research
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• v.51 no.1
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• pp.37-46
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• 2011

Infectious bursal disease virus (IBDV) is a member of the Avibirnavirus genus of the Birnaviridae family which genome consists of two segments (A and B) of double stranded RNA. Segment A gene of KNU08010 isolate, which was isolated from a 15-day-old chicken flock in 2008, was sequenced and compared with other IBDV isolates including SH/92 strain, the first Korean very virulent (vv) IBDV isolate. The amino acid sequences of segment A gene showed that KNU08010 had 99.2% homology with SH92 strain. KNU08010 isolate had specific amino acids A222, I242, I256, I294 and S299 which are highly conserved among vvIBDV strains. Phylogenetic analysis based on the nucleotide sequences of variable region of the VP2 gene of 18 IBDV strains revealed that KNU08010 was grouped with vvIBDVs and was closely related to Korean vvIBDVs isolated from wild birds.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.563-566
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• 1998

Two soybean cultivars, Kwanggyo and Hwanggeum (soybean mosaic potyvirus (SMV)-resistant cultivars), that had been inoculated with a virulent strain (G-5H, 4) of soybean mosaic potyvirus produced necrotic lesions on inoculated leaves as well as on upper trifoliate leaves. Cells in the lesion area contained sparse numbers of virus particles and very few characteristic pinwheel inclusions. Although a hypersensitive-like cellular response occurred in the two resistant cultivars, this response did not prevent the virus from spreading systemically in these resistant hosts, indicating a different mechanism from the general hypersensitive reaction in relation to host resistance.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.6
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• pp.679-684
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• 1996

This study evaluates the susceptibility of scaleless mutant chickens to very virulent Marek's disease virus (vvMDV) inoculation. One day old chickens were inoculated subcutaneously with Taiwanese isolates of LTB-1 and LTS-1 strains, and standard strain of Md/5. Compared with the non-inoculated group the vvMDV-inoculated chickens showed decreased body weights and atrophy of lymphoid organs before 35 days old. These results indicate that scaleless chickens show the same susceptibility as the wild type chickens to vvMDV infection. Furthermore, the protective effect of herpesvirus of turkey (HVT) vaccination at 1 day old against vvMDV challenge was evaluated. Scaleless mutant chickens of treated groups showed 20-30% early death, and 85.7-100% and 12.5-14.2% had lymphomatous lesions in visceral organs and peripheral nerves, respectively. No significant lesions were observed in non-challenged chickens of the control group. The HVT vaccination did not provide an effective protection against vvMDV infection. It is concluded that scaleless mutant chickens are susceptible to vvMDV infection.

• Journal of Veterinary Clinics
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• v.18 no.1
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• pp.55-60
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• 2001

Immunohistochemical and Electron Microscopical Studies on the Initial Skin Lesions Induced Experimentally by Very Virulent Strain of Marek\`s Disease Virus in Chickens Marek\`s disease virus (MDV), which is an avian herpesvirus, causes malignant CD3+CD4+CD8-T cell lymphomas at many sites including visceral organs, muscles, peripheral nerves and skin. In the early skin lesions induced by MDV, corelationship between the translational activity of MDV early gene, pp38 and demonstration of MDV particles in the lymphoid cells are not well studied. Therefore, skin biopsies taken at weekly intervals for 2 weeks from the same specific-pathogen free chicknes inoculated with Md/5 MDV were examined immunohistochemically and electron microscopically. In the skin biopsies sampled at 1 week and 2 weeks post inoculation (PI), feather follicle epithelium (FFE) exhibited usually strong positive reaction for pp38, whereas only few lymphoblasts, which were infiltrated around FFE revealed positive reaction. Electron microscopically, small lymphocytes were detectable in the dermis and subcutaneous skin tissues sampled at 1 week PI. The number of small lymphocytes was increased and pleomorphic lymphoblasts, which were medium to large in size were scattered among the small lymphocytes at 2 weeks PI. Some of lymphoblasts revealed degenerative and necrotic changes. FFE contained a lot of MDV particles in the nucleus including mature and immature ones. Infrequently, immature virus particles were observed not only in the degenerative and necrotic lymphoblasts, but also rarely in the health lymphoblasts. From the present results, spontaneous MDV activation including translational activity of MDV pp38 gene and formation of MDV particles was occurred in the lymphoblasts of early MD skin lesions.

• Korean Journal of Veterinary Research
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• v.39 no.3
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• pp.545-553
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• 1999

A 474-base pair segment covering the hypervariable region of VP2 gene from six Korean infectious bursal disease virus(K-IBDV) isolates(K1, K2, SH/92, 225, 269, 310) and one attenuated IBDV(DAE) were amplified using RT-PCR, sequenced, and compared with published sequences for IBDV. K-IBDV isolates(K1, K2, SH/92, 225, 269) and foreign very virulent(vv) IBDV strains had 94.93~100% amino acid sequence similarity. K-IBDV isolate 310 and other K-IBDV isolates had 84.31~86.07% amino acid sequence similarity. Attenuated strain(DAE), like other attenuated strain, has substitution at positions 279(D to N) and 284(A to T) as well as in the serine-rich heptapeptide region. Five K-IBDV isolates except 310 isolate share unique amino acid residues at positions 222(A), 256(I), 294(I) which are not present in other standard and attenuated strains. At the two hydrophilic region, K-IBDV isolates except 310 isolate had identical amino acids comparing with Belgium vv IBDV 894VB but had four amino acid substitutions comparing with Chinese vv IBDV F9502. The SWSASGS heptapeptide is conserved in all K-IBDV isolates. The sequence of K-IBDV isolate 310 was markedly different from other IBDV strains, evolving from a separate lineage than the others. By phylogenetic analysis, Five K-IBDV isolates except 310 isolate were categorized in one group with foreign vv IBDV isolates but K-IBDV isolate 310 was categorized in a separate group which was differentiated from other compared IBDV strains.

• The Journal of Korean Physical Therapy
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• v.10 no.2
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• pp.113-125
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• 1998

The neurotropic psudorabies virus(PRV) to replicate within neurons is very useful pathogen for neuronal tracing. I carried out this study to investigate the parametric analysis on the viral infection in the rat circadian control center with two genetically engineered strains out of PRV. The two strains are isogenic with the attenuated Bartha strain of PRV ; in one strain a lacZ reporter gene was inserted into the gC locus (PRV-BaBlu ; $4.75\times10^8pfu/ml$) and the other strain contained a PRV envelope glycoprotein gene(PRV-D ; $2.5\times10^8pfu/ml$) theat is absent in PRV-BaBlu. simultaneous or temporally separated sequential injection of$2{\mu}l$ of each strain into the vetreous body of eye produced a course of transsynaptic infection of retinohypothalamic circuitry. The results were as follows; 1. PRV-BaBlu and PRV-D infected the suprachiasmatic nucleus in hypothalamus and intergeniculate leaflet in lateral geniculate nucleus of thalamus. 2. The rate of PRV infection was dependent upon PRV strain. 3. Pre-infected neurons by PRV-D were interfered with the replication of PRV-BaBlu. 4. Dual injection of PRV-D and PRV-BaBlu showed more virulent than the parental strain.

• Korean Journal of Veterinary Service
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• v.35 no.2
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• pp.91-97
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• 2012

The strategy for infectious bursal disease (IBD) control and its success rate under field conditions depends on hygiene management, IBD field pressure, level, and variation in maternally derived IBD antibodies. This study investigated the level of IBD-specific antibody by ELISA and the prevalence of IBD virus by PCR in broilers, white-semi broilers, and Korean native chickens raised in Jeongeup, Jeonbuk. IBD-specific maternally derived antibodies were measured from 698 chickens and the mean titers of maternal antibodies were $3,572{\pm}1,402$ in broilers, $1,262{\pm}762$ in white-semi broilers, and $1,932{\pm}912$ in Korean native chickens. At 2 weeks after vaccination, the geometric mean antibody titers of broiler, white-semi broiler, and Korean native chicken were $582{\pm}427$, $3255{\pm}1,080$, and $1,023{\pm}499$, respectively. According to sequence analysis of the variable virion protein 2 gene, 4 isolates were found to be very virulent IBDV, 9 isolates classical virulent, and 2 isolates intermediate plus vaccine strain.

• Journal of Microbiology and Biotechnology
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• v.26 no.1
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• pp.197-206
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• 2016

Listeria monocytogenes is a foodborne pathogen of considerable genetic diversity with varying pathogenicity. Initially, we found that the strain M7 was far less pathogenic than the strain Lm850658 though both are serovar 4a strains belonging to the lineage III. Comparative genomic approaches were then attempted to decipher the genetic basis that might govern the strain-dependent pathotypes. There are 2,761 coding sequences of 100% nucleotide identity between the two strains, accounting for 95.7% of the total genes in Lm850658 and 92.7% in M7. Lm850658 contains 33 specific genes, including a novel 20K prophage whereas strain M7 has 130 specific genes, including two large prophages (38K and 44K). To examine the roles of these specific prophages in pathogenicity, the 20K and 38K prophages were deleted from their respective strains. There were virtually no differences of pathogenicity between the deletion mutants and their parent strains, although some putative virulent factors like VirB4 are present in the 20K region or holin-lysin in the 38K region. In silico PCR analysis of 29 listeria genomes show that only strain SLCC2540 has the same 18 bp integration hotspot as Lm850658, whereas the sequence identity of their 20K prophages is very low (21.3%). The 38K and 44K prophages are located in two other different hotspots and are conserved in low virulent strains M7, HCC23, and L99. In conclusion, the 20K and 38K prophages of L. monocytogenes serovar 4a strains Lm850658 and M7 are not related to virulence but contribute to genetic diversity.

• Korean Journal of Veterinary Research
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• v.41 no.3
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• pp.373-380
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• 2001

Marek's disease virus (MDV) can cause skin lesions including inflammatory to tumorous. The phenotypical changes of lymphocytes infiltrating in the skin lesions induced by MDV were not clear. Therefore, the skin biopsies taken at weekly intervals for 8 weeks from the same specific-pathogen free chickens inoculated with Md/5 MDV were examined to analysis the phenotypical changes of lymphocytes. Histologically skin lesions progressed from initial inflammatory to late tumorous. Sequentially CD4+ T lymphocytes increased gradually in number from initial skin lesions and were major composition cells in the tumor lesions. Regardless of inflammatory or tumor lesions, CD8+ T cells and ${\gamma}{\delta}$ T cells infiltrated particularly in the dermis and subcutaneous on which MDV was actively replicated in the feather follicle epithelium(FFE). In addition, IgG bearing B lymphocytes in considerable number infiltrated in the dermis and subcutaneous tissues. From these results, the development of MDV-induced skin lesions was inflammatory following tumorous. In addition, each CD8+, ${\gamma}{\delta}$ and CD4+ T cells and B cell might act to protect MDV replication in the FFE or tumor cells which turned on lytic cycle.